yes, fraid so, lose about 3 mpg and its noisy, but not excessive, lets face it, you only use it for the journey to holiday/camp etc.
When you get there thewhole bars and box combo comes off as one in 90 seconds - Altea roof bars have an excellent mechanism hat undoes with a key. So while your running around on holiday, the box is off...... When you go home again put the box back on in 90 seconds!!